Making the case for an International Childhood Cancer Data Partnership.

Childhood cancers are a heterogeneous group of rare diseases, accounting for less than 2% of all cancers diagnosed worldwide. Most countries, therefore, do not have enough cases to provide robust information on epidemiology, treatment, and late effects, especially for rarer types of cancer. Thus, only through a concerted effort to share data internationally will we be able to answer research questions that could not otherwise be answered. With this goal in mind, the US National Cancer Institute and the French National Cancer Institute co-sponsored the Paris Conference for an International Childhood Cancer Data Partnership in November 2023. This meeting convened more than 200 participants from 17 countries to address complex challenges in pediatric cancer research and data sharing. This Commentary delves into some key topics discussed during the Paris Conference and describes pilots that will help move this international effort forward. Main topics presented include: (1) the wide variation in interpreting the European Union's General Data Protection Regulation among Member States; (2) obstacles with transferring personal health data outside of the European Union; (3) standardization and harmonization, including common data models; and (4) novel approaches to data sharing such as federated querying and federated learning. We finally provide a brief description of 3 ongoing pilot projects. The International Childhood Cancer Data Partnership is the first step in developing a process to better support pediatric cancer research internationally through combining data from multiple countries.